Laboratory techniques for diagnosis of chlamydial infections of the eye

Giemsa and fluorescence antibody (FA) staining were used to diagnose patients clinically suspected to be suffering from trachoma. A total of 52 controls i.e. individuals with refractive errors and no clinical trachoma and 173 cases suffering from different stages of trachoma were studied. FA was found to be 2.52 times more sensitive in confirming the presence of Chlamydia trachomatis compared to Giemsa staining. 28/52 (53.8%) and 4/52 (7.,69%) controls were also positive by FA and Giemsa staining, respectively, indicating sub-clinical infection without symptoms. Post treatment staining with both methods revealed that clinical cure of trachoma did not necessarily mean the absence of Chlamydia trachomatis in the conjunctival smears. As a corollary it can be deduced that mere presence of Chlamydia trachomatis in conjunctival epithelial cells may not cause clinical trachoma, certain host factors (local immunity etc.) may play an important role in clinical disease.